Golf club head and method for producing the same

Abstract

A golf club head comprises an outer titanium club-head shell, and a titanium sole portion integrally coupled to the outer club-head shell. A weight fitting hole is bored in the sole portion, and a plurality of cutouts are formed in the inner peripheral edge portion of the fitting hole. A weight made of metal having a specific gravity higher than that of titanium is inserted into the fitting hole, and the weight is fixed to the sole portion after press-deformed so that its outer peripheral edges are press-fitted into the respective cutouts. A method for producing a golf club head comprises the steps of molding the outer club-head shell from titanium, molding the sole portion having the weight fitting hole from titanium, forming the plurality of cutouts in the inner peripheral edge portion of the fitting hole of the sole portion, inserting the weight made of metal having a specific gravity higher than that of titanium into the fitting hole, fixing the weight to the sole portion by press-deforming the weight in such a way as to press-fit the outer peripheral edges of the weight into the respective cutouts, and coupling the outer club-head shell and the sole portion integrally by welding.

What is claimed is: 
     
       1. A golf club head comprising an outer titanium club-head shell, and a titanium sole portion integrally coupled to the outer club-head shell wherein a weight fitting hole is bored in said sole portion; a plurality of cutouts are formed in an inner peripheral edge portion of said fitting hole; a weight made of metal having a specific gravity higher than that of titanium is inserted into said fitting hole; and said weight is fixed to said sole portion by being press-deformed so that outer peripheral edges of the weight are press-fitted into said respective cutouts. 
     
     
       2. A golf club head as claimed in claim 1, wherein the inner peripheral edge portion of said fitting hole include inner and outer faces and is formed stepwise in the thickness direction of the sole portion; and said weight is press-deformed so that its outer peripheral edges clamp both the inner and outer faces of said inner peripheral edge portion. 
     
     
       3. A golf club head as claimed in claim 1, wherein said metal having a higher specific gravity is at least a metal selected from the group consisting of steel, nickel alloy and tungsten alloy. 
     
     
       4. A golf club head as claimed in claim 1, wherein a sealing material is poured into a gap between said fitting hole and said weight to seal up said gap. 
     
     
       5. A golf club head as claimed in claim 4, wherein said sealing material is metal solder. 
     
     
       6. A golf club head as claimed in claim 1 that is a wood type golf club head. 
     
     
       7. A golf club head as claimed in claim 1 that is an iron type golf club head. 
     
     
       8. A method for producing a golf club head comprising the steps of molding an outer club-head shell from titanium, molding a sole portion having a weight fitting hole from titanium, forming a plurality of cutouts in a inner peripheral edge portion of said fitting hole of said sole portion, inserting a weight made of metal having a specific gravity higher than that of titanium into said fitting hole, fixing said weight to said sole portion by press-deforming said weight in such a way as to press-fit outer peripheral edges of said weight into said respective cutouts, and coupling said outer club-head shell and said sole portion integrally by welding. 
     
     
       9. A method for producing a golf club head as claimed in claim 8, further comprising the steps of forming the inner peripheral edge portion of said fitting hole stepwise in the thickness direction of the sole portion, wherein said inner peripheral edge portion includes inner and outer faces; and press-deforming said weight so that its outer peripheral edges clamp both the inner and outer faces of said inner peripheral edge portion. 
     
     
       10. A method for producing a golf club head as claimed in claim 8, wherein said metal having a higher specific gravity is at least one metal selected from the group consisting of steel, nickel alloy and tungsten alloy. 
     
     
       11. A method for producing a golf club head as claimed in claim 8, further comprising the step of pouring a sealing material into a gap between said fitting hole and said weight to seal up said gap. 
     
     
       12. A method for producing a golf club head as claimed in claim 11, wherein said sealing material is metal solder.